Articulated immersion heater



July 7, 1970 -"r. s. KINNEY ARTICULATED IMMERSION HEA TER Filed April 1, 1968 I I I I N VENYY )R. f /fdmf 5 AVA/MW United States Patent O 3,519,795 ARTICULATED IMMERSION HEATER Theodore S. Kinney, Rte. 1, Box 595X, Poulsbo, Wash. 98370 Filed Apr. 1, 1968, Ser. No. 717,579 Int. Cl. F2411 1/18; Hb 1/00 US. Cl. 219-310 1 Claim ABSTRACT OF THE DISCLOSURE BACKGROUND Long, high capacity electric immersion heaters are variously used to raise the temperatures of fluids contained in tanks and vessels. A typical installation occurs in the road building business in connection with heating road oils and the like. The installation of such heaters during manufacture of the tanks and vessels is desirable. However, their replacement or supplementation in the field, especially where the tank or vessel is underground or torch cutting and welding is impractical or unduly costly, presents substantial problems. One solution to the problem is to provide a lengthy, flexible heater unit that may be inserted through an access opening usual in such tanks and vessels in the upper areas. Such a heater is shown in my US. Pat. No. 2,888,546 where a fully flexible corrugated sheath was employed to encase a unidirectionally flexible electric resistance assembly. It has been found that due to the length of such shields, there is a practical problem of adequately degreasing the interior of the sheath. Also, inspection of the sheath, which is ordinarily manufactured from shaped metallic ribbons welded together, to determine that it is fluid-tight throughout its length is time-consuming and costly. And where the resistance is unidirectionally flexible but concealed within the flexible sheath the installers risk internal and hidden damage unless great care is taken to determine orientation of the heater unit at the point where flexure is desired.

PURPOSES It has, therefore, been among the main objectives of this invention to provide a fluid-tight sheathed electric resistance heater unit which is universally flexible; which has flexibility provided at only those points where needed to effect installation through a side wall of an elongated tank or vessel; which is simple and economical to construct and install; and which may be installed by relatively unskilled workers in the field without resort to heating or special manipulation. These and other objects will become apparent during the course of the following description of a preferred embodiment of the invention.

IN THE DRAWINGS FIG. 1 shows an elongated universally flexible assembly of insulated resistance elements, a portion being omitted for convenience of illustration;

FIG. 2 is a perspective view of an insulator;

FIG. 3 is a face view of an insulator as installed in a tubular sheath;

FIG. 4 is an enlarged portion of the assembly of FIG. 1;

FIG. 5 shows an articulated electric immersion heater unit according to this invention, portions being omitted for illustrative convenience;

FIG. 6 shows a mode of installation of such an articulated heater unit in a vessel; and

FIG. 7 schematically shows a typical electric resistance element assembly.

DESCRIPTION Insulator 10, formed of ceramic or similar material, is generally circular in profile having a flat 12 which aids in assembly and has functions during use. The opposite faces 14 are convex and apertures 16 extend therebetween. Essentially the apertures 16 are round holes having diametrically opposed grooves, as shown in FIG. 2.

In an assembly of insulators 10, as shown in FIG. 4, an initial few receive bars 18 to which the inner ends of spiral resistance elements 20 are attached as by screws 22. Elements 20 are resilient lengthwise and may be expanded and contracted as the assembly is flexed. Elements 20 extend longitudinally of a long assembly of insulators and link them together in a flexible manner so that the convex faces 14 of adjacent insulators are in contact but may be misaligned as when the assembly is bent out of a straight line.

Supply wires 24 are conductively attached to the inner ends of bars 18. The outer ends of elements 20 attach to a conductive collar 26 disposed between the last two insulators and 27 of the assembly. Bolt 28 which axially passes through insulators 25 and 27 and intervening collar 26 as well as a small insulative collar 30. Nut 32 on bolt 28 bears on the terminal insulator 27 and tightens together the components of the terminal assembly.

A fluid-tight articulated sheath encases an assembly, as described in the manner best shown in FIG. 5. Such a sheath comprises at least a pair of elongated inflexible tubes 34 and 36, the latter being referred to as the outer tube and having a closed end 38. Inner tube 34 may be threaded to receive a junction box or other fitting 39. Tubes 34, 36 are sequentially arranged and are coupled together in an articulated manner by a manually flexible joint section 40. The flexible joint section may be formed integral with tubes 34 and 36, or it may be separately formed and then integrated into the sheath assembly.

Joint section 40 has a length substantially less than the length of either of the tubes. The function of section 40 is to permit manual flexing of the sheath assembly with misalignment of the tubes 34, 36 being restricted to joint section 40. Thus, the length of the section need be only suflicient to permit tubes 34 and 36 to be misaligned up to about with respect to each other.

Articulating joint section 40 may be either annularly or spirally corrugated metal of a thickness (about 0.020 to 0.040 inch) and structure and length permitting manual flexing, preferably without heating. Section 40 may be formed in situ in a mid-portion of a long tube or it may be separately formed and then welded in place between a pair of tubes 34, 36.

Flexure of joint section 40, as well as flexure of the insulated resistance elements 20, is universal. This means that the angular disposition of a component on one side of a bend occurring within joint section 40 may be in any radial direction with respect to the axis of the other component on the opposite side of the bend. When the sheath encases the resistance unit, bending of the latter and misalignment of blocks 10, is localized in the area within section 40. However, extensive and compressive forces within the coiled resistance elements is not so localized but is distributed in both directions from the point of bend. Thus, undue strain on the resistance elements through the area of a manually flexible joint 40 is avoided.

In FIG. 6 tank or vessel is shown provided with an upper manhole or other access port usually located some distance from an end of the vessel. It is a practical impossibility to insert a rigid heater unit of length substantially the same as the interior length of vessel 50 through opening 52. By providing an articulated heater unit, as described, an outer tube portion 36 may first be inserted and angularly disposed somewhat as shown. By bending the unit at joint 40, the inner tube 34 then may be introduced while at the same time tube 36 is further advanced within the vessel 50. Finally, a standpipe 54, which may also include a flexible section 55 and a return bend portiton 56, and is connected to junction box 39, is disposed in the opening where it may be secured to receive power supplied to conductors 24 therein.

The invention has been described with reference to a unit comprising two elongated rigid tubes and one intermediate articulating coupler section 40. Also on occasion to facilitate introducing the heater unit, the forward end may have a flexible section 41 adjacent the end closure 38. It will be apparent to those skilled in the art that to accommodate certain circumstances the unit may have more than two rigid sections in which case an additional one or more manually flexible sections 40 will be employed. Other changes as in material, size and proportion and the like are contemplated.

What is claimed is:

1. The combination, comprising:

an elongated horizontal vessel to contain fluid to be heated and having an access port in the top side thereof;

an elongated immersion heater in said vessel, including:

a fluid tight sheath comprising at least two sequentially arranged inflexible tubes, coupled endto-end by a universally and manually flexible joint section;

means sealing the remote end of said sheath;

References Cited UNITED STATES PATENTS 1,699,323 1/1929 Apfel 219-335 X 2,888,546 5/1959 Kinney 219-335 X 3,013,108 12/1961 Sweeney 174-99 3,060,069 10/1962 Sindars 15445 3,286,078 11/1966 Hynes 219-335 X FOREIGN PATENTS 155,417 2/ 1954 Australia.

OTHER REFERENCES Rex-Flex Stainless Steel Flexible Tubing, a pamphlet published by Chicago Metal Hose Corporation, Maywood, 111. Received in US. Patent Oflice Dec. 23, 1940, 7 pages.

JOSEPH V. TRUHE, Primary Examiner C. L. ALBRI'I'TON, Assistant Examiner US. Cl. X.R. 2l9316, 335 

